do you think that the manufacturers have made them safer in recent years?
Absolutely, both chargers and batteries have come on leaps and bounds in the last 5 years.
Problem is though, even if it's 1 in a million chance that the batteries fizz, the consequences of a unattended lithium battery fire is extremely dire.
Even IF you manage to catch it before it ignites nearby things, the smoke is extremely acidic, very dense and an absolute nightmare to clean up after, it basically means that anything the smoke comes into contact with will rot within a short period of time.
I was reading a report a few months back where the health and safety executive in the US said that there are fires in the US caused by lithium batteries daily.
Be it people falling to sleep with their laptop on their bed and it self igniting from overheating, or laptops left plugged in 24/7.
It's nothing to put the charger in a well ventilated location and keep and eye on it while charging.
Yet such a small compromise will dramatically reduce even a small risk.
So my advice is, buy decent cells, buy a decent charger, do not charge inside the torch and NEVER leave any batteries charging unattended (i've seen NiMh's exploded and turn the owners car into a shell before the fire department arrived).